refs #10765 - Token: introduced cache for isAliasOf() calls

Author: firewave

lib/astutils.cpp

@@ -2947,7 +2947,7 @@ static bool isExpressionChangedAt(const F& getExprTok,
             Token::Match(tok->astOperand2() ? tok->astOperand2() : tok->astOperand1(), "%varid%", expr->varId()))
             aliased = true;
         if (!aliased)
-            aliased = isAliasOf(tok, expr, &i);
+            aliased = tok->isAliasOf(expr, &i);
         if (!aliased)
             return false;
         i += indirect;

lib/token.cpp

@@ -2753,3 +2753,19 @@ const SmallVector<ReferenceToken>& Token::refs(bool temporary) const
         mImpl->mRefs.reset(new SmallVector<ReferenceToken>(followAllReferences(this, false)));
     return *mImpl->mRefs;
 }
+
+bool Token::isAliasOf(const Token* expr, int* indirect) const
+{
+    const auto it = utils::as_const(mImpl->mAliases).find(expr);
+    if (it != mImpl->mAliases.cend()) {
+        if (indirect)
+            *indirect = it->second.second;
+        return it->second.first;
+    }
+    int i = 0;
+    const bool b = ::isAliasOf(this, expr, &i);
+    mImpl->mAliases[expr] = std::make_pair(b, i);
+    if (indirect)
+        *indirect = i;
+    return b;
+}

lib/token.h

@@ -41,6 +41,7 @@
 #include <set>
 #include <string>
 #include <type_traits>
+#include <unordered_map>
 #include <utility>
 #include <vector>
 
@@ -173,6 +174,8 @@ class CPPCHECKLIB Token {
         std::unique_ptr<SmallVector<ReferenceToken>> mRefs;
         std::unique_ptr<SmallVector<ReferenceToken>> mRefsTemp;
 
+        std::unordered_map<const Token*, std::pair<bool, int>> mAliases;
+
         void setCppcheckAttribute(CppcheckAttributesType type, MathLib::bigint value);
         bool getCppcheckAttribute(CppcheckAttributesType type, MathLib::bigint &value) const;
 
@@ -1364,6 +1367,8 @@ class CPPCHECKLIB Token {
     // provides and caches result of a followAllReferences() call
     const SmallVector<ReferenceToken>& refs(bool temporary = true) const;
 
+    bool isAliasOf(const Token* expr, int* indirect) const;
+
     /**
      * Sets the original name.
      */